Grundy County Climate
Grundy County, Iowa
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
47.1°F
Annual Precip
37.2"
Annual Snowfall
32.0"
Extreme Heat Days
11
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
5a
Minimum winter temperature range for plant survival
2,866
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Grundy County
Climate Verdict
Grundy County has a cool, averaging 47.1°F annually, moderate rainfall of 37.2 inches per year, rare extreme heat with only 11.4 days above 90°F annually, moderate snowfall of 32.0 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 17.4°F. summers are warm — July averages 72.7°F. Residents experience a substantial 55°F difference between winter and summer.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Grundy County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Grundy County closely matches the Iowa statewide average temperature of 48.0°F.
Climate Profile
About Grundy County Weather
Cooler than the national median
Grundy County averages 47.1°F annually, reflecting a cooler humid continental climate. The county receives 37.2 inches of precipitation, which is typical for the American heartland.
Slightly cooler than state average
The county's 47.1°F average is roughly one degree cooler than the Iowa state average of 48.0°F. However, it is wetter than the state norm, receiving 37.2 inches of rain compared to 36.1 inches.
Warmer than Fayette and Hamilton
At 47.1°F, Grundy is notably warmer than Hamilton County’s 46.1°F. It experiences a similar snowfall level to Greene County, recording 32.0 inches annually.
Damp years and moderate summers
Grundy sees 11 days of 90°F heat during its 70.9°F average summer. Winters are cold and snowy, with a January average of 17.4°F and 32.0 inches of total snowfall.
Manage moisture and winter chill
With 37.2 inches of annual precipitation, ensuring proper property drainage is essential. Residents should also prepare for a 20.9°F winter average with robust home heating.
Frequently Asked Questions
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Data sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.
Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.